With the advance of integrated circuit (IC), a CPU is made more and more compact and has a higher speed than old ones. Thereby, a great deal of heat is generated. However in current trend, it is desired that the electronic devices have compact size, that is, they are smaller, and more and more peripherals are added to the computer, such as CD drive, hard disk drive, etc., and thus, it is required that the heat dissipating devices of those devices are compact with a powerful heat dissipating ability.
In the prior art power supply, the fan is vertical arranged in the casing of a power supply so that the height of the power supply can not be reduced. Since the fan is vertically arranged, the shaft for rotating the fan must support the weight of the fan. Thereby, the wearing between the shaft and the bearing is dramatic and thus, the lifetime is reduced. Furthermore, the blades of the fan is tightly adhered to the via holes for dissipating heat. The noise is large.
To improve above said defect, a large fan is added to the casing of the computer mainframe so as to have two heat dissipating effect by the fans in and out of the casing. However, since work is easy, but another fan is necessary so that the cost is high.